It has come to my attention over the last few days that the search on my site had stopped working for no apparent reason. It had stopped working on my Development environment first, then shortly after on my live environment. I noticed the issue when I would create a blog post and it would error when trying to insert the new data into the solr index.
I did some basic research to no avail to find the problem when I finally rooted it out in the live environment that my search service was trying to access a core in another person's hosting directory which I did not have access to. I asked the host provider to give me some insight on what they could do, and they pointed me to the problem.
list: returns a query result set, named from the name attribute value, of the attributes of the collections that are registered by ColdFusion. If you have Solr collections and omit the engine attribute, ColdFusion lists information for both types of collections.
It actually returns a query of all collections registered on the ColdFusion server, including those some other instances. To resolve this, we reference a UDF on CFLib called collectionExists.
I needed to modify the function for CF10
<cfsearch name="searchItems" collection="#arguments.collection#" type="simple" criteria="#createUUID()#" />
<cfsearch name="searchItems" collection="#arguments.collection#" criteria="#createUUID()#" />
After that, solr was up and running again. I rebuilt the indexes to make sure everything was in place and I was done.